Supersensitized photographic emulsions containing polymethine dyes and ketones



SUPERSENSITIZED PHOTOGRAPHIC 'EMULSIONS POLYMETHINE DYES AND KE- Jean E. Jones, Rochester, N. Y., Kodak Company, Rochester, N. New Jersey Application May 21, 1956,- Serial No. 586,056 17 Claims. 01. 96-104 assignor to Eastman Y., a corporation of United States Patent altered by varying the conditions in the emulsion. For

example, the sensitization may be increased by increasing the silver ion concentration or decreasing the hydrogen ion concentration (i. e., increasing the alkalinity) or both. Thus, sensitization can be increased by bathing plates,

- coated with a spectrally sensitized emulsion, in water or in aqueous solutions of ammonia. Such a process of altering the sensitivity of a sensitized emulsion by increasing the silver ion concentration and/ or by decreasing the hydrogen ion concentration is commonly called hypersensitization. Hypersensitized emulsions have generally poor keeping qualities.

I have now found a new means of altering the sensitivity in emulsions containing cyanine dyes. Since the conditions in the emulsion, i. e., the hydrogen ion and/ or the silver ion concentration undergo little or no change in my method,,I shall designate my new method as a kind of supersensitization.

It is, therefore, an object of my invention to provide photographic emulsions containing certain polymethine dyes and, as supersensitizers therefor, certain ketone'compounds. Another object is to provide a process for preparing these sensitized emulsions; Other objects will be: come apparent from a consideration of the following description and examples. v

The polyniethine dyes useful in practicing my invention can advantageously be represented by the following two general formulas:

wherein R represents a lower alkyl group, such as methyl, ethyl, etc., R represents a lower alkyl group, such as methyl, ethyl, etc., R represents a lower alkoxyl group, such as methoxyl, ethoxyl, etc., and R and R together represent the atoms necessary to complete a cyclopentane ring (i. e., R and R together represent a trimethylene group), R represents a hydrogen atom, a lower alkyl group (e. g., methyl, ethyl, etc.), a lower alkoxyl group (e. g., methoxyl, ethoxyl, etc.), a monocyclic aryl group (e. g., phenyl, tolyl, etc.), or a heterocyclic group (e. g., thienyl, etc.), and Z and Z each represents the nonmetallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole series, a heterocyclic nucleus of the naphthothiazole series (e. g., a heterocyclic nucleus of the fl-naphthothiazole series, etc.), or'a "heterocyclic nucleus of the benzoxazole series, provided that when Z represents the non-metallic atoms necessary to complete'a' heterocyclic nucleus of the benzothiazole series, R represents an ethyl group and R represents a hydrogen atom. The heterocyclic nuclei represented by Z andZ can have substituents attached to the benzene rings thereof, such as chlorine, bromine, methyl, phenyl, hydroxyl, etc.

The ketone compounds useful in practicing my invention can advantageously be represented by the following two general formulas: '1 i and i wherein D represents a dialkylaminoaryl group (e. g., dimethylaminophenyl, diethylaminophenyl, etc.) or a pyrryl group (e. g., 1-aryl-2,5-dimethyl-3-pyrryl, wherein the aryl group is a monocyclic aryl group, such as phenyl, tolyl, etc.), R represents an aryl group (e. g., phenyl, tolyl, naphthyl, etc., especially an aryl group containing from 6 to '10 carbon. atoms), a dialkylaminoarylvinyl group (e. g., dimethylaminophenylvinyl, diethylaminophenylvinyl, etc.) or a dialkylaminoaryl-l,3-butadienyl group (e. g., dimethylaminophenyl-l,B-butadienyl, diethylaminophenyl-l,3-butadienyl, etc.), R and R each represents a lower alkyl group, such as methyl, ethyl, etc., and n represents a positive integer of from 1 to 2.

Polyrnethine dyes selected from those represented by Formulas vI and 11 above which can advantageou ly be I v s I 014T o=on-on=en-on= \CN 5 3115 2- (5,5-dieyano-2,4-pentadienylidene) 13 ethylbenzothiazo1ine h lt W Y 2- (5,5-dicyano-4-ethoxy-3-methyl-2,4-pentadienylidene) 3-ethylbenzothiazoline I 1-d1cyanomethy1ene-2-[ (3-e thyl-2 (3H -benzothiazo1y1idene)- ethylidenekyelopentane Patented Nov. 18, 1958 pentanone 2-(5,5-dicyano-2,4-pentadienylidene)-1-ethy1-B-naphtho- (F) thiazoline V H3C\ ('2') C=CHCH=CHC=C H3O Hzb CH1 (lJHz 2,5-di (p-dimethylnminobenzal) cyclopentanone N According to my invention, I incorporate one or more an, of the polymethine dyes selected from those represented by Formulas I or II above with one or more of the ketone compounds selected from those represented by Formulas III or IV above in a photographic emulsion. My invention is particularly directed to the ordinarily employed (6) S ON gelatino-silver-halide emulsions. However, my supersensitizing combinations can be employed in silver halide emul- 2-(5,5 dicyano-4-methyl-2,4-pentadieny1idene)-1-ethylnaphthothiazoline v =CH CH:CH C=O\ sions in which the carrier is other than gelatin, e. g., a

/ C5115 ON resinous substance or cellulosic material which has no deteriorating effect on the silver-halides.

I 235 My invention is primarily directed to the ordinarily employed gelatino-silvenhalide developing-out emulsions,

2-(5,S-dicyano4-phenyl-2,4-pentadieny1idene)-1-ethy1-B- e. g., gelatinceilver-chloride, -chlorobromide, -chloronaphthothiazoline iodide, -chlorobromiodide, -bromide and -bromiodide de- (7) s veloping-out emulsions. While the results in the followcN ing examples were obtained using gelatino-silver-bromio- C=CH CH=CH C=O/ dide emulsions, useful results have also been obtained using gelatino-silver-chlorobromide emulsions. Particu- /C:CH ON larly improved sensitizing activity has been obtained in J s gelatino-silver-bromiodide emulsions of the developing- \C=CH out type. Emulsions which form the latent image mostly inside the silver halide grains, such as the'emulsions set 2-(5,5-dieyano-4-(2-thienyl)-2,4-pentadieny1idene)-1-ethyl-B- forth in U. S. Patent 2,456,956, dated December 21, 1948,

naphthmhiamnne can also be employed in practicing my invention. (8) 0 40 The emulsions prepared in accordance with my invention can be coated in the usual manner on any suitable C=CH-GH=GH-O=C support, e. g., glass, cellulose nitrate film, cellulose acetate 0H3 0N film, polyvinyl acetal resin film, glycol terephthalate film, N polystyrene film, paper, metal, etc. (32m The sensitizing dyes and ketone compounds can be employed in various concentrations depending upon the gggfiggfigt elfects desired. As is well known in the art, the sensitivity conferred upon an emulsion by a sensitizing dye does not Ket011e 0mP0undS represelltbd y Formulas III and IV increase proportionately .to the concentration of the dye above which can advantag ly be p y in y in the emulsion, but rather passes through an optimum Ventlon q p the ketbne compounds represented y as the concentration is increased. In practicing my intbe foubwlng formulas: vention, the individual sensitizing dyes are advantageously (A) 0 employed at approximately their optimum concentration g (i. e., the concentration at which the individual dyes give greatest sensitivity). In general, the ketone compounds CH3 represented by'Formulas III and IV above have little or -pJDimethylaminocinnamalacetophenone no sensitizing action on the emulsions. (B) BIG 0 CH; ll /N'CH=CH-CH=OH-CCH=CHCH=CHi Hi0 \CH; Dl-p-dimethylaminocinnamalacetone (C) 0 CH3 The optimum concentration of a sensitizing dye can be c ll determined in a manner well known to those skilled in the art by measuring the sensitivity of a series of test .por-

tions of the same emulsion, each portion containing a difpe y no a acetophenone ferent concentration of the sensitizing dye. The optimum (D) 0 concentration of my supersensitizing combinations can, of l course, be readily determined in the same manner, by \C measuring the sensitivity of a series of test portions of the same emulsion, each portion containing a different concentration of the sensitizing .dye used in the combinap-Dimethylaminobenza1-2-acetonaphthalene 75, ti n- In determining the optimum concentration for the supersensitizing combination, it is advantageous to em-' ploy, at first, a concentration of the sensitizing dye some- What less than its optimum concentration. The concentration of the dye can then be increased until the optimum concentration suitable for use in the combination is determined.

Ordinarily, the optimum or near optimum concentration of the dyes selected from those represented by Formula I or II above which I employ in practicing my invention is of the order of from .05 to .30 gram per mol. of silver halide in the emulsion.

The ketone compounds selected from those represented by Formula III or IV above are advantageously employed in concentrations on the order of from .1 to 1.0 gram per mol. of silver halide in the emulsion.

Generally speaking, the concentration of the dye of Formula I or II to the ketone compound of Formula III or IV can vary rather widely in my combinations, e. g., from 1:1 to 1:20 (by weight) in many cases.

The methods of incorporating sensitizing dyes and ketone compounds in emulsions are well known to those skilled in the art. In practicing my invention, the sensitizing dyes and ketone compounds can be incorporated in the emulsions separately or together. It is convenient to add the dyes and ketone compounds separately in the form of solutions in appropriate solvents. Acetone has provensatisfactory as a solvent for many of the compounds selected from Formulas I-IV which I employ, although pyridine has been found to be satisfactory in certain cases. The dyes and ketone compounds are advantageously incorporated in the finished, washed emulsions and should be uniformly distributed throughout the emulsions. The following procedure is satisfactory: Stock solutions of the sensitizing dyes and ketone compounds described are prepared by dissolving the same in appropriate solvents as described above. Then, to the flowable gelatino-silver-halide emulsion, the desired amounts of the stock solution of one of the dyes or ketone compounds is slowly added, while stirring the emulsion. Stirring is continued until the dye is thoroughly incorporated in the emulsion. Then, the desired amount of the stock solution of the second ingredient (dye or ketone compound) is slowly added to the emulsion, while stirring. Stirring is continued until the second ingredient is thoroughly incorporated. Alternatively, the stock solutions of the dye and ketone compound can be intermixed before addition to the emulsion. Also, instead of using a single dye or ketone compound, a plurality of each can be employed to advantage. The supersensitized emulsion can then be coated out on a suitable support, such as glass, cellulose nitrate film, cellulose acetate film, resin film, paper, etc., to a suitable thickness and allowed to dry. The details of such coating methods are well known to those skilled in the art.

The amounts of sensitizing dye and ketone compound actually incorporated in the emulsion will vary somewhat from case to case, according to the emulsion employed, particular dye and ketone compound employed, and according to the effect desired. The regulation and adoption of the most economical and useful proportions will be apparent to those skilled in the art upon making the ordinary observations and tests customarily employed in the art. Accordingly, the foregoing procedures and proportions are to be regarded only as illustrative. Clearly my invention is directed to any emulsion containing a combination of the aforesaid sensitizing dyes and ketone compounds, whereby the emulsion has a speed greater than that obtainable with either type of ingredient alone.

The following examples will serve to illustrate further the manner of practicing my invention: To different portions of the same batch of photographic gelatino-silverbromiodide emulsion were added (1) a sensitizing dye selected from those of Formula I or II above and (2) a combination of the sensitizing dye of Formula I or II and a ketone compound selected from those represented these emulsions when so employed. While differentemulsion batches were employed in some of the examples, the same emulsion batches were employed for the coatings in each individual example. Before coating out the emulsions on the support, the emulsions containing the addenda were digested for a short time in a tank maintained'at about 50 C. The different portions of emulsion were then coated on supports and exposed in the usual manner in a spectrograph and a sensitometer (Type Ib) through a Wratten No. 12 filter, i. e., a filter which transmits substantially no light of wavelength shorter than about 495 mu. The 30/E speed (minus blue), gamma and fog obtained after development of the exposed emulsions are given below. The developer employed had the following composition:

p-N-methylamlnophenol sulfate 2.0

Hydroqumone 8.0

Sod1un1 sulfite (anhydrous) 90.0

Sodium carbonate monohydrate 52.5

Potassium br mid 5.0 Water to make one liter.

Dye Ketone 30/E Example (g./mol. (g./mol. Speed Gamma Fog ketone compounds represented by Formulas III or IV above to advantage. I have also found that certain polymethine dyes corresponding to those of Formulas I or II above wherein Z or Z represent a heterocyclic nucleus other than benzothiazole, naphthothiazole or benzoxazole can be employed to advantage in certain instances. For example, such dyes wherein Z or Z represent the nonmetallic atoms necessary to complete a heterocyclic nucleus of the thiazoline series (e. g., 2-(5,5-dicyano-4- ethoxy-2,4-pentadienylidene)-3-methylthiazoline), can be employed in combination with the ketone compounds of Formulas III or IV, such as compound A. However, such combinations are not generally as useful as the combinations shown in the above table.

I have also found that compounds corresponding to those of Formulas I or II above, except that one of the cyano groups is replaced by a carbalkoxyl group can also be employed in combination with the ketone compounds of Formulas III or IV. Such derivatives of the compounds of Formulas I or II are shown in U. S. Patent No. 2,697,707 and Belgian Patent 506,549.

The accompanying drawing illustrates the supersensitizing effect obtained with three of my new combinations of polymethine dyes and ketone compounds in gelatino' silver-bromiodide emulsions. Each figure of the drawing is a diagrammatic reproduction of two spectrograms. In each figure, the sensitivity of the emulsion containing only the polymethine dye of Formulas I or II is represented by the solid curve. The sensitivity of the emulsion containing both the polymethine dye of Formulas I or II and the ketone compounds of Formulas III or IV is represented by the curve consisting of short dashes. No curve showing the sensitivity of the emulsion containing the ketone compounds of Formulas III or IV is shown, since these compounds have no measurable effect on the emulsion employed.

In Figure 1, curve A represents the sensitivity of an ordinary gelatino-silver-bromiodide emulsion sensitized with 2 (5,5 dicyano 2,4 pentadienylidene) 3- ethylbenzothiazoline, while curve B represents the sensitivity of the same emulsion sensitized with 2-(5,5-dicyano 2,4 pentadienylidene) 3 ethylbenzothiazoline and p-dimethylaminocinnamalacetophenone. The sensitometric measurements for these emulsions are given in Example 1 of the above table.

In Figure 2, curve C represents the sensitivity of an ordinary gelatino-silver-bromiodide emulsion sensitized with 2 (5,5 dicyano 4 ethoxy 3 methyl 2,4- pentadienylidene) 3 ethylbenzothiazoline, while curve D represents the sensitivity of the same emulsion sensitized with 2-(5,5-dicyano4-ethoxy-3-methyl-2,4-pentadienylidene) 3 ethylbenzothiazoline and p dimethylaminocinnamalacetophenone. The sensitometric measurements for these emulsions are given in Example 2 of the above table.

In Figure 3, curve B represents the sensitivity of an ordinary gelatino-silver-bromiodide emulsion sensitized with 2 (5,5 dicyano 4 methyl 2,4 pentadienylidene) 1 ethyl B naphthothiazoline, while curve F represents the sensitivity of the same emulsion sensitized with 2 (5,5 dicyano 4 methyl 2,4 pentadienylidene) 1 ethyl ,8 naphthothiazoline and p dimethylaminocinnamalacetophenone. The sensitometric measurements for these emulsions are given in Example 3 of the above table.

Photographic silver halide emulsions, such as those listed above, containing the supersensitizing combinations of my invention can also contain such addenda as chemical sensitizers, e. g., sulfur sensitizers (e. g., allyl thiocarbamide, thiourea, allylisothiocyanate, cystine, etc.), various gold compounds (e. g., potassium chloroaurate, auric trichloride, etc.) (see U. S. Patents 2,540,085; 2,597,856 and 2,597,915), various palladium compounds, such as palladium chloride (U. S. 2,540,086), potassium chloropalladate (U. S. 2,598,079), etc., or mixtures of such sensitizers; antifoggants, such as ammonium chloroplatinate (U. S. 2,566,245), ammonium chloroplatinite (U. S. 2,566,263), benzotriazole, nitrobenzimidazole, 5- nitroindazole, benzidine, mercaptans, etc. (see Mees The Theory of the Photographic Process, Macmillan Pub., 1942, page 460), -or mixtures thereof; hardeners, such as formaldehyde (U. S. 1,763,533), chrome alum (U. S. 1,763,533). glyoxal (U. S. l,370,354), dibromacrolein (Br. 406,750), etc., color couplers, such as those described in U. S. Patent 2,423,730, Spence and Carroll U. S. Patent 2,640,776, issued June 2, 1953, etc.; or mixtures of such addenda. Dispersing agents for color couplers, such as those set forth in U. S. Patents 2,322,027 and 2,304,940, can also be employed in the above-described emulsions.

Many of the polymethine dyes represented by Formulas I or 11 above can be prepared according to known methods. For example, U. S. Patent 2,697,707, issued December 21, 1954, describes the preparation of certain of these dyes. Belgian Patent 506,549, granted Novemher 14, 1951, also describes the preparation of certain of these polymethine dyes.

Many of the ketone compounds represented by Formulas III or IV above are also known substances. For example, British Patent 512,477 and German Patent 810,458 describe the preparation of certain of these ketone compounds.

The following examples will serve to illustrate further the preparation of certain of these polymethine dyes represented by Formulas I or II and the ketone compounds of Formulas III or IV.

Example A .-2- (5 ,5 -dicyano-2,4-pentadienylidene)-1 ethylnaphth0[1,2] thiazoline A mixture of 5.26 g. (1 mol.) of 2-(4-acetanilido-1,3- butadienyl) 1 ethylnaphtho[1,3]thiazolium iodide, 3.3 g. (1 mol. plus 400% excess) of malononitrile, 15 ml. of ethyl alcohol and 1.01 g. (1 mol.) of triethylamine was heated at the refluxing temperature for 10 minutes. After chilling, the solid was collected on a filter and washed with methyl alcohol. The yield of product was 30% crude and 19% after two purifications, each of which consisted of dissolving the crystals in 50 ml. of hot pyridine, filtering the solution and then adding ml. of methyl alcohol to the filtrate. The dark bluish crystals had M. P. 278-279 C. with decomposition.

2 (5,5 dicyano 2,4 pentadienylidene) 3 ethylbenzothiazoline was prepared, in like manner, by using 4.76 g. (1 mol.) of 2-(4-acetanilido-1,3-butadenyl)-3- ethylbenzothiazolium iodide in place of the 2 (4- acetanilido 1,3 butadienyl) 1 ethylnaphtho[1,2]- thiazolium iodide in the above example. The yield of product was 43% crude and 30% after two purifications, each of which consisted of dissolving the crystals in 50 ml. of hot pyridine, filtering the solution and then adding 300 ml. of methyl alcohol to the filtrate. The felt of steel blue needles had M. P. 245246 C. with decomposition.

Example B.2,5-di[ (2,5-dimethyl-J-phenyl-3-pyrryl) methylene]-cycl0pentan0ne A solution of 1.68 g. (1 mol.) of cyclopentanone and 8.75 g. (1 mol. plus 10% excess) of 2,5-dimethyl-lphenylpyrrole-3-carboxaldehyde in 20 ml. of ethyl alcohol was heated to the boiling point, a solution of 2.5 g. of 40% sodium hydroxide was added and the reaction mixture was allowed to cool to room temperature. The solid was collected on a filter and washed with methyl alcohol. The yield of product was 76% after two purifications, each of which consisted of dissolving the crystals in hot pyridine, filtering the solution and adding methyl alcohol to the filtrate. The yellow needles had M. P. 274-275" C. with decomposition.

Example C.p-Dimethylaminobenzal-Z-acetonaphthalene To a solution of g. of p-dimethylaminobenzaldehyde and 11.7 g. of B-acetonaphthone in 200 ml. of ethanol were added 3 ml. of 40% sodium hydroxide solution. The mixture was allowed to stand at room temperature for -18 hours. There was a change from yellow to reddish-orange during the first few hours and a solid separated while standing. The solid was collected on a filter, washed with a little ethanol containing a little acetic acid, and dried. The crude product, M. P. 99- 104 C., weighed 11.4 g. (56%). Recrystallization from ethanol gave 10.5 g. of pure product melting at 109-110 C.

Analysis.For C H ON: Calcd: N, N, 4.8.

Example D.-p-Dimethylaminocinnamalacetophenone A mixture of 3.5 g. of p-dimethylaminocinnamaldehyde, 2.4 g. of acetophenone, and 40 ml. of alcohol was warmed and 4 ml. of 10% aqueous sodium hydroxide 4.7. Found:

'were added. After standing overnight, the product had crystallized in gleaming red plates. The yield of once recrystallized ketone was 3.8 g. (72% M. P. 151-153 C.

I have also found that polymethine dyes corresponding to those represented by Formulas I and II above wherein Z and Z each represent a heterocyclic nucleus other than those illustrated above can sometimes be employed to advantage in my supersensitizing combinations. For example, such dyes wherein Z or Z represent the nonmetallic atoms necessary to complete a heterocyclic nucleus of the thiazole series can be employed in certain cases in combination with the ketone compounds .of my invention. An example of such polymethine dye is 2-(5,5-dicyano-4@ethoXy-2,4-pentadienylidene)-3 methylthiazolidine. This dye has been found to give useful results in combination with the ketone compounds of Formulas III or IV, such as compound A above.

The polymethine dyes of my invention wherein R and R together represent the atoms necessary to complete a cyclopentane ring can advantageously be prepared according to the method described in U. S. Patent 2,697,707 (corresponds to British 704,770 and 704,840), and as further illustrated'in my copending application Serial No. 586,053, filed on even date herewith.

What I claim as my invention and desire, secured by Letters Patent of the United States is: v

1. 'A photographic silver halide emulsion sensitized with a supersensitizing combination of at least one polymethine dye selected from those represented by the following three general formulas:

wherein R and R each represents'an alkyl group containing from 1 to 2 carbon atoms, R represents an alkoxyl group containing from 1 to 2 carbon atoms, Z and Z each represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of those of the benzothiazole series, those of the naphthot'hiazole series, and those of the benzoxazole series, and R represents a' member selected from the group consisting of a hydrogen atom, an alkyl group containing from 1. to 2 carbon atoms, an alkoxyl group containingfrom 1 tof2 carbon atoms, a monocyclic aryl group, and a thienyl group, provided thatwhen Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole series, R represents an ethyl group and R represents a hydrogen atom, and at least one ketone compound selected from those represented by the following general formulas:

wherein D represents a member selected from the group consisting of a dialkylaminoaryl group wherein the alkyl groups contain froml to 2 carbon atoms and a pyrryl group, R represents a member selected from the group consisting of an aryl group, a dialkylaminoarylvinyl group wherein the alkyl groups contain from 1 to 2 carbon atoms and a dialkylaminoaryl-l,3-butadienyl group wherein the alkyl groups contain from 1 to 2 carbon atoms, R and R each represents an alkyl group containing from 1 to 2 carbon atoms, and n represents a positive integer of from 1 to 2.

. 2. A photographic gelatino-silver-halide developingout emulsion sensitized with-a supersensitizing combination of at leastone polymethine dye selected from those taining from 1 to 2 carbonatoms, R represents an alkoxyl group containing from 1 to 2 carbon atoms, Z and Z each represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of those of the benzothiazole series, those of the naphthothiazole series, and those of the benzoxazole series, and R represents'a member selected from the group consisting of a hydrogen atom, an alkyl group containing from 1' to 2 carbon atoms, an alkoxyl group containing from 1 to 2 carbon atoms, a monocyclic aryl group, and a thienyl group, provided that when Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole series, R represents an ethyl group and R represents a hydrogen atom, and at least one ketone compound selected from those represented by the following general formulas:

and

wherein D represents a member selected from the group consistingof a dialkylaminoaryl group wherein the alkyl groups contain from 1 to '2 carbon atoms and .a pyrryl group, R represents a member selected from the group consisting of an aryl group, a dialkylaminoarylvinyl group wherein the alkyl groups contain from 1 to 2 carbon atoms and a dialkylaminoaryl-l,3-butadienyl group wherein the lower alkyl groups contain from 1 to 2 carbon atoms, R and R each represents an alkyl group containing from 1 to 2 carbon atoms, and n represents a positive integer of from 1 to 2.

3. A photographic gelatino-silver-bromiodide developing-out emulsion sensitized witha supersensitizing combination of at least one polymethine dye selected from those represented by the following three general formulas:

wherein R and R each represents an alkyl group containing from 1 to 2 carbon atoms, R represents an alkoxyl group containing from 1 to 2 carbon atoms, Z and Z each represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of those of the benzothiazole series, those of the naphthothiazole series, and those of the benzoxazole series, and R represents a member selected from the group consisting of a hydrogen atom, an alkyl group containing from 1 to 2 carbon atoms, an alkoxyl group containing from 1 to 2 carbon atoms, a monocyclic aryl group, and a thienyl group, provided that when Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole series, R represents an ethyl group and R represents a hydrogen atom, and at least one ketone compound selected from those represented by the following general formulas:

wherein D represents a member selected from the group consisting of a dialkylaminoaryl group wherein the alkyl groups contain from 1 to 2 carbon atoms and a pyrryl group, R represents a member selected from the group consisting of an aryl group, a dialkylaminoarylvinyl group wherein the alkyl groups contain from 1 to 2 carbon atoms and a dialkylaminoaryl-l,3-butadieny1 group wherein the alkyl groups contain from 1 to 2 carbon atoms, R and R each represents an alkyl group containing from 1 to 2 carbon atoms, and n represents a positive integer of from 1 to 2.

4. A photographic gelatino-silver-halide developingout emulsion sensitized with a supersensitizing combination of at least one polymethine dye selected from those represented by the following three general formulas:

and

R1 R: CN

wherein R and R each represents a member selected from the group consisting of a methyl group and an ethyl group, R represents a member selected from the group consisting of a methoxyl group and an ethoxyl group, Z and Z each represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of those of the benzothiazole series, those of the naphthothiazole series and those of the benzoxazole series, and R represents a member selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a methoxyl group, an ethoxyl group, a phenyl group, and a thienyl group, provided that when 2, represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole series, R represents an ethyl group and R represents a hydrogen atom, and at least one ketone compound selected from those represented by the following two general formulas:

0 l DHo=o-(i 3=cHD H, CH1

and

0 R: H Rro-0H=oH(oH=oH)H N\ wherein D represents a member selected from the group consisting of a di(lower alkyl)aminoaryl group wherein the lower alkyl groups contain from 1 to 2 carbon atoms and a 1-aryl-2,5-dimethyl-3-pyrrole group wherein the aryl group is a monocyclic aryl group, R represents a member selected from the group consisting of an aryl group containing from 6 to 10 carbon atoms, a di(lower alkyl)aminoarylvinyl group wherein the lower alkyl groups contain from 1 to 2 carbon atoms, and a di(lower alkyl)aminoaryl-l,3-butadienyl group wherein the lower alkyl groups contain from 1 to 2 carbon atoms, R and R each represents a member selected from the group consisting of a methyl group and an ethyl group, and n represents a positive integer of from 1 to 2.

5. A photographic gelatino-silver-halide developingout emulsion as defined in claim 4 wherein the silver halide is silver-bromiodide.

6. A photographic gelatino-silver-halide developingout emulsion sensitized with a supersensitizing combination of a dye selected from those represented by the fo1- lowing general formula:

/Zl- CN If o=oH-oH=orr-oH=o 02H; CN

wherein R represents a member selected from the group consisting of an aryl group containing from 6 to 10 carbon atoms,'a di(lower alkyl) aminoarylvinyl groupwherein the lower alkyl groups contain from 1 to 2 carbon atoms, and a di(lower alkyl)aminoaryl-1,3-butadienyl group whereinthe lower alkyl groups contain froml to 2 carbon atoms, R and R each represents a member selected from the group consisting of a methyl group and an {ethyl group and n represents a'positive integer of from ltoz, I

"7. A photographic gelatino-silver-halide developingout emulsion sensitized with "a supersensitizing combination of a dye selected from those represented by the following generalformula: l 1

wherein Zi represents thenon metallic atoms necessary to complete a heterocyclic nucleus -of the benzothiazole series,apd-a ketone compound selected from those represented by the following general formula:

wherein- R represents'an aryl group containing from 6 to carbon1atoms', R and R each represents a member selected from the group consisting of a methyl group and wherein Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole I series, and a ketone compound selected from those represented by the following general formula:

, by the following general formula:

wherein R represents a member selected from the group consisting of a methyl group and an ethyl group, R represents a member selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a phenyl group and a thienyl group, and Z represents non-metallic atoms necessary to complete a heterocyclic nucleus of the naphthothiazole series, and a ketone compound selected from those represented by the following general formula:- g

carbon atoms, R5 and R each represents a member selected from the group consisting of a methyl group and an ethyl group and n represents a positive integer of from 1 to 2.

12. A photographic gelatino-silver-halide developingout emulsion sensitized with a supersensitizing combination of a polymethine dye selected from those represented by the following general formula:

1 (Zh ON {I it wherein R represents a member selected from the group consisting of a methyl group and an ethyl group, R represents a member selected from the group consisting of a.

hydrogen atom, a methyl group, an ethyl group, a phenyl group and a thienyl group, and Z represents the nonmetallic atoms necessary to complete a heterocyclic nucleus of the naphthothiazole series, and a ketone compound selected from those represented by the following general formula:

wherein R represents .an aryl group containing from 6 to 10 carbon atoms, R and R each represents a member selected from the group consisting of a methyl group and an ethyl group, and n represents a positive integer of from 1 to 2.

13. A photographic gelatino-silver-halide developingout emulsion sensitized with a supersensitizing combination of 2-(5,5dicyano-4-methyl-2,4-pentadienylidene)lethyl-fi-naphthothiazoline and p-dimethylaminocinnamalacetophenone.

14. A photographic gelatino-silver-halide developingout emulsion sensitized with a supersensitizing combination of 2-(5,5dicyano4-phenyl-2,4-pentadienylidene)1- ethyl-B-naphthothiazoline and p-dimethylaminobenzalacetophenone.

15. A photographic gelatino-silver-halide developingout emulsion sensitized with a supersensitizing combination of a polymethine dye selected from those represented by the following general formula:

wherein R represents a member selected from the group consisting of a methyl group and an ethyl group, R represents a member selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a

phenyl group and a thienyl group, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzoxazole series, and a ketone compound selected from those represented by the following general formula:

an ethyl group and n represents a positive integer of 10 from 1 to 2.

16. A photographic gelatino-silver-halide developingout emulsion sensitized with a supersensitizing combination of a polymethine dye selected from those represented by the following general formula:

C=CHCH=CH('3=C R3 CN wherein R represents a member selected from the group consisting of a methyl group and an ethyl group, R represents a member selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a phenyl group and a thienyl group, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzoxazole series, and a ketone compound 16 selected itrom those represented by the following general formula: I

wherein R4, represents an aryl group containing from 6 to 10 carbon atoms, R and R each represents a member selected from the group consisting of a methyl group and an ethyl group, and n represents a positive integer of from 1 to 2. t

17. A photographic gelatino-silver halide developingout emulsion sensitized with a supersensitizing combina' tion of 2-(S,5-dicyano-4-methyl-2,4-pentadienylidene)-3- ethylbenzoxazoline and p-dimethylaminocinnomalacetophenone.

References Cited thejile of this patent UNITED STATES PATENTS Kendallet a1. mega-1, 1954 FOREIGN PATENTS 681,432 Great Britain Oct.22, 1952 686,733 Great Britain Ian. 28, 1953 vised ed., Macmillan Co., N. Y., 1954, pages 376 and UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,860,984 November 18, 1958 Jean E. Jones It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 8, line 24, Example A, for [1,3] read [1,2]; line 37, for 1,3- butadenyl) -3- read -1,3-butadienyl)-3-; column 16, line 15, claim 17 for p-dimethylaminocinnomalaceto read p-dimethylaminocinnamalaceto- Signed and sealed this 7th day of April 1959.

Att'esh KARL H. AXLINE, Attesti/ng Officer. A

ROBERT C. WATSON,

- Uom/missz'mr of Patents. 

1. A PHOTOGRAPHIC SILVER HALIDE EMULSION SENSITIZED WITH A SUPERSENTIZING COMBINATION OF AT LEAST ONE POLYMETHINE DYE SELECTED FROM THOSE REPRESENTED BY THE FOLLOWING THRE GENERAL FORMULAS: 